A new kind of silica gel confined ionic liquid containing a metal complex as heterogenized catalysts was prepared for the carbonylation of amines and nitrobenzene without molecular oxygen to afford the corresponding ureas with greatly enhanced catalytic activity (TOF exceeded 11000mol.mol(-1). h(-1)), with a much lower amount of ionic liquids being needed, with easy catalyst separation and possible reusability, and avoidance of the using of explosive CO + O-2 gas mixtures. Such an enhancement in catalytic activity may be derived from the effect of a high concentration of ionic liquid containing a metal complex due to the confinement into the nanopores or cavities of the silica gel matrix.

★★★☆☆ Keywords: amines; carbonylation; ionic liquids; nitrobenzene; phosgene-free

★★★☆☆ Adv. Synth. Catal. 2005, 347, 225 –230.